[JJ_SO]

maybe I was not clear: I already have this thing since two years. It's alright to use it, but

• my Tamron G2 has a better collar and I like it's Arca rail very much. Also, the lens is just light enough for handheld shots - for tripod, I use a Gimbal, a levelling ball and a Gitzo Series 4.
  
• my Nikkor 300 PF-E is a bit too short and the diameter is too small to fit (although the lenshood does fit)
  
• It's useful for landscape-oriented shots - that's a downside to the collars (but Mengs also offers various copies of standard collars)
  
• I don't know the genuine part of that lens bracket, but the Chinese made a nice copy of it.
  

The macro rail sold by Mengs for around 20$ as a "panorama tilt rail" (2 macro tails combined) is nothing for high-precision stacking or smooth opartion - but occassionally used, it's okay.